Low and High BMI Increases Risk of Death

Ivanhoe Newswire
Wednesday, August 23, 2006; 12:00 AM

(Ivanhoe Newswire) -- When it comes to weight, people who are right in the middle are likely to live longer lives. Two new studies reveal being overweight or underweight increases risk of death.

Researchers in the United States and researchers in Korea used data from two separate populations to draw their conclusions. While theories about body mass index and its relationship to death risks have recently come under fire, both studies found BMI could predict the likelihood of an increased death risk.

In the Korean study, researchers used data on more than 1 million Korean men and women to investigate the link between body weight and the risk of death. For this population, the average BMI was 23.2. Investigators report people outside of the middle BMI range, 23 to 24.9, have a higher risk of death than people within the middle range.

The cause of death varied depending on which end of the weight spectrum a person was. The underweight were more likely to die of respiratory illness, while the overweight were more likely to die of cardiovascular disease or cancer. These results, report researchers, cannot be generalized to other populations because of the difference between the number of respiratory causes of death in Koreans compared to Western countries.

In the second study, researchers from the National Cancer Institute in Bethesda, Md., compiled data on more than 500,000 U.S. men and women between ages 50 and 71.

Researchers report risk of death increased at both extremes of the body weight spectrum. When the researchers looked only at healthy non-smokers, the risk of death was most concentrated in overweight and obese people.

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SOURCE: The New England Journal of Medicine, 2006:355;763-778:779-787